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FFmpeg/libavcodec/ratecontrol.c

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/*
Copyright (C) 2002 Michael Niedermayer <michaelni@gmx.at>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <inttypes.h>
#include <stdio.h>
#include "common.h" //needed for mpegvideo.h to compile
#include "dsputil.h" //needed for mpegvideo.h to compile
#include "avcodec.h"
#include "mpegvideo.h"
#define STATS_FILE "lavc_stats.txt"
static int init_pass2(MpegEncContext *s);
void ff_write_pass1_stats(MpegEncContext *s){
RateControlContext *rcc= &s->rc_context;
// fprintf(c->stats_file, "type:%d q:%d icount:%d pcount:%d scount:%d itex:%d ptex%d mv:%d misc:%d fcode:%d bcode:%d\")
fprintf(rcc->stats_file, "in:%d out:%d type:%d q:%d itex:%d ptex:%d mv:%d misc:%d fcode:%d bcode:%d\n",
s->picture_number, s->input_picture_number - s->max_b_frames, s->pict_type,
s->qscale, s->i_tex_bits, s->p_tex_bits, s->mv_bits, s->misc_bits, s->f_code, s->b_code);
}
int ff_rate_control_init(MpegEncContext *s)
{
RateControlContext *rcc= &s->rc_context;
emms_c();
if(s->flags&CODEC_FLAG_PASS1){
rcc->stats_file= fopen(STATS_FILE, "w");
if(!rcc->stats_file){
fprintf(stderr, "failed to open " STATS_FILE "\n");
return -1;
}
} else if(s->flags&CODEC_FLAG_PASS2){
int size;
int i;
rcc->stats_file= fopen(STATS_FILE, "r");
if(!rcc->stats_file){
fprintf(stderr, "failed to open " STATS_FILE "\n");
return -1;
}
/* find number of pics without reading the file twice :) */
fseek(rcc->stats_file, 0, SEEK_END);
size= ftell(rcc->stats_file);
fseek(rcc->stats_file, 0, SEEK_SET);
size/= 64; // we need at least 64 byte to store a line ...
rcc->entry = (RateControlEntry*)av_mallocz(size*sizeof(RateControlEntry));
for(i=0; !feof(rcc->stats_file); i++){
RateControlEntry *rce;
int picture_number;
int e;
e= fscanf(rcc->stats_file, "in:%d ", &picture_number);
rce= &rcc->entry[picture_number];
e+=fscanf(rcc->stats_file, "out:%*d type:%d q:%d itex:%d ptex:%d mv:%d misc:%d fcode:%*d bcode:%*d\n",
&rce->pict_type, &rce->qscale, &rce->i_tex_bits, &rce->p_tex_bits, &rce->mv_bits, &rce->misc_bits);
if(e!=7){
fprintf(stderr, STATS_FILE " is damaged\n");
return -1;
}
}
rcc->num_entries= i;
if(init_pass2(s) < 0) return -1;
}
/* no 2pass stuff, just normal 1-pass */
//initial values, they dont really matter as they will be totally different within a few frames
s->i_pred.coeff= s->p_pred.coeff= 7.0;
s->i_pred.count= s->p_pred.count= 1.0;
s->i_pred.decay= s->p_pred.decay= 0.4;
// use more bits at the beginning, otherwise high motion at the begin will look like shit
s->qsum=100 * s->qmin;
s->qcount=100;
s->short_term_qsum=0.001;
s->short_term_qcount=0.001;
return 0;
}
void ff_rate_control_uninit(MpegEncContext *s)
{
RateControlContext *rcc= &s->rc_context;
emms_c();
if(rcc->stats_file) fclose(rcc->stats_file);
if(rcc->entry) free(rcc->entry);
rcc->stats_file= NULL;
rcc->entry= NULL;
}
//----------------------------------
// 1 Pass Code
static double predict(Predictor *p, double q, double var)
{
return p->coeff*var / (q*p->count);
}
static void update_predictor(Predictor *p, double q, double var, double size)
{
double new_coeff= size*q / (var + 1);
if(var<1000) return;
p->count*= p->decay;
p->coeff*= p->decay;
p->count++;
p->coeff+= new_coeff;
}
int ff_rate_estimate_qscale(MpegEncContext *s)
{
int qmin= s->qmin;
int qmax= s->qmax;
int rate_q=5;
float q;
int qscale;
float br_compensation;
double diff;
double short_term_q;
double long_term_q;
double fps;
int picture_number= s->input_picture_number - s->max_b_frames;
int64_t wanted_bits;
emms_c();
fps= (double)s->frame_rate / FRAME_RATE_BASE;
wanted_bits= (uint64_t)(s->bit_rate*(double)picture_number/fps);
// printf("%d %d %d\n", picture_number, (int)wanted_bits, (int)s->total_bits);
if(s->pict_type==B_TYPE){
qmin= (int)(qmin*s->b_quant_factor+0.5);
qmax= (int)(qmax*s->b_quant_factor+0.5);
}
if(qmin<2) qmin=2;
if(qmax>31) qmax=31;
if(qmax<=qmin) qmax= qmin;
/* update predictors */
if(picture_number>2){
if(s->pict_type!=B_TYPE && s->last_non_b_pict_type == P_TYPE){
//printf("%d %d %d %f\n", s->qscale, s->last_mc_mb_var, s->frame_bits, s->p_pred.coeff);
update_predictor(&s->p_pred, s->last_non_b_qscale, s->last_non_b_mc_mb_var, s->pb_frame_bits);
}
}
if(s->pict_type == I_TYPE){
short_term_q= s->short_term_qsum/s->short_term_qcount;
long_term_q= s->qsum/s->qcount*(s->total_bits+1)/(wanted_bits+1); //+1 to avoid nan & 0
q= 1/((1/long_term_q - 1/short_term_q)*s->qcompress + 1/short_term_q);
}else if(s->pict_type==B_TYPE){
q= (int)(s->last_non_b_qscale*s->b_quant_factor+0.5);
}else{ //P Frame
int i;
int diff, best_diff=1000000000;
for(i=1; i<=31; i++){
diff= predict(&s->p_pred, i, s->mc_mb_var) - (double)s->bit_rate/fps;
if(diff<0) diff= -diff;
if(diff<best_diff){
best_diff= diff;
rate_q= i;
}
}
s->short_term_qsum*=s->qblur;
s->short_term_qcount*=s->qblur;
s->short_term_qsum+= rate_q;
s->short_term_qcount++;
short_term_q= s->short_term_qsum/s->short_term_qcount;
long_term_q= s->qsum/s->qcount*(s->total_bits+1)/(wanted_bits+1); //+1 to avoid nan & 0
// q= (long_term_q - short_term_q)*s->qcompress + short_term_q;
q= 1/((1/long_term_q - 1/short_term_q)*s->qcompress + 1/short_term_q);
}
diff= s->total_bits - wanted_bits;
br_compensation= (s->bit_rate_tolerance - diff)/s->bit_rate_tolerance;
if(br_compensation<=0.0) br_compensation=0.001;
q/=br_compensation;
//printf("%f %f %f\n", q, br_compensation, short_term_q);
qscale= (int)(q + 0.5);
if (qscale<qmin) qscale=qmin;
else if(qscale>qmax) qscale=qmax;
if(s->pict_type!=B_TYPE){
s->qsum+= qscale;
s->qcount++;
if (qscale<s->last_non_b_qscale-s->max_qdiff) qscale=s->last_non_b_qscale-s->max_qdiff;
else if(qscale>s->last_non_b_qscale+s->max_qdiff) qscale=s->last_non_b_qscale+s->max_qdiff;
}
//printf("q:%d diff:%d comp:%f rate_q:%d st_q:%f fvar:%d last_size:%d\n", qscale, (int)diff, br_compensation,
// rate_q, short_term_q, s->mc_mb_var, s->frame_bits);
//printf("%d %d\n", s->bit_rate, (int)fps);
return qscale;
}
//----------------------------------------------
// 2-Pass code
static int init_pass2(MpegEncContext *s)
{
RateControlContext *rcc= &s->rc_context;
int i;
double fps= (double)s->frame_rate / FRAME_RATE_BASE;
double complexity[5]={0,0,0,0,0}; // aproximate bits at quant=1
double avg_quantizer[5];
uint64_t const_bits[5]={0,0,0,0,0}; // quantizer idependant bits
uint64_t available_bits[5];
uint64_t all_const_bits;
uint64_t all_available_bits= (uint64_t)(s->bit_rate*(double)rcc->num_entries/fps);
int num_frames[5]={0,0,0,0,0};
double rate_factor=0;
double step;
int last_i_frame=-10000000;
/* find complexity & const_bits & decide the pict_types */
for(i=0; i<rcc->num_entries; i++){
RateControlEntry *rce= &rcc->entry[i];
if(s->b_frame_strategy==0 || s->max_b_frames==0){
rce->new_pict_type= rce->pict_type;
}else{
int j;
int next_non_b_type=P_TYPE;
switch(rce->pict_type){
case I_TYPE:
if(i-last_i_frame>s->gop_size/2){ //FIXME this is not optimal
rce->new_pict_type= I_TYPE;
last_i_frame= i;
}else{
rce->new_pict_type= P_TYPE; // will be caught by the scene detection anyway
}
break;
case P_TYPE:
rce->new_pict_type= P_TYPE;
break;
case B_TYPE:
for(j=i+1; j<i+s->max_b_frames+2 && j<rcc->num_entries; j++){
if(rcc->entry[j].pict_type != B_TYPE){
next_non_b_type= rcc->entry[j].pict_type;
break;
}
}
if(next_non_b_type==I_TYPE)
rce->new_pict_type= P_TYPE;
else
rce->new_pict_type= B_TYPE;
break;
}
}
complexity[rce->new_pict_type]+= (rce->i_tex_bits+ rce->p_tex_bits)*(double)rce->qscale;
const_bits[rce->new_pict_type]+= rce->mv_bits + rce->misc_bits;
num_frames[rce->new_pict_type]++;
}
all_const_bits= const_bits[I_TYPE] + const_bits[P_TYPE] + const_bits[B_TYPE];
if(all_available_bits < all_const_bits){
fprintf(stderr, "requested bitrate is to low\n");
return -1;
}
// avg_complexity= complexity/rcc->num_entries;
avg_quantizer[P_TYPE]=
avg_quantizer[I_TYPE]= (complexity[I_TYPE]+complexity[P_TYPE] + complexity[B_TYPE]/s->b_quant_factor)
/ (all_available_bits - all_const_bits);
avg_quantizer[B_TYPE]= avg_quantizer[P_TYPE]*s->b_quant_factor;
//printf("avg quantizer: %f %f\n", avg_quantizer[P_TYPE], avg_quantizer[B_TYPE]);
for(i=0; i<5; i++){
available_bits[i]= const_bits[i] + complexity[i]/avg_quantizer[i];
}
//printf("%lld %lld %lld %lld\n", available_bits[I_TYPE], available_bits[P_TYPE], available_bits[B_TYPE], all_available_bits);
for(step=256*256; step>0.0000001; step*=0.5){
uint64_t expected_bits=0;
rate_factor+= step;
/* find qscale */
for(i=0; i<rcc->num_entries; i++){
RateControlEntry *rce= &rcc->entry[i];
double short_term_q, q, bits_left;
const int pict_type= rce->new_pict_type;
int qmin= s->qmin;
int qmax= s->qmax;
if(pict_type==B_TYPE){
qmin= (int)(qmin*s->b_quant_factor+0.5);
qmax= (int)(qmax*s->b_quant_factor+0.5);
}
if(qmin<2) qmin=2;
if(qmax>31) qmax=31;
if(qmax<=qmin) qmax= qmin;
switch(s->rc_strategy){
case 0:
bits_left= available_bits[pict_type]/num_frames[pict_type]*rate_factor - rce->misc_bits - rce->mv_bits;
if(bits_left<1.0) bits_left=1.0;
short_term_q= rce->qscale*(rce->i_tex_bits + rce->p_tex_bits)/bits_left;
break;
case 1:
bits_left= (available_bits[pict_type] - const_bits[pict_type])/num_frames[pict_type]*rate_factor;
if(bits_left<1.0) bits_left=1.0;
short_term_q= rce->qscale*(rce->i_tex_bits + rce->p_tex_bits)/bits_left;
break;
case 2:
bits_left= available_bits[pict_type]/num_frames[pict_type]*rate_factor;
if(bits_left<1.0) bits_left=1.0;
short_term_q= rce->qscale*(rce->i_tex_bits + rce->p_tex_bits + rce->misc_bits + rce->mv_bits)/bits_left;
break;
default:
fprintf(stderr, "unknown strategy\n");
short_term_q=3; //gcc warning fix
}
if(short_term_q>31.0) short_term_q=31.0;
else if (short_term_q<1.0) short_term_q=1.0;
q= 1/((1/avg_quantizer[pict_type] - 1/short_term_q)*s->qcompress + 1/short_term_q);
if (q<qmin) q=qmin;
else if(q>qmax) q=qmax;
//printf("lq:%f, sq:%f t:%f q:%f\n", avg_quantizer[rce->pict_type], short_term_q, bits_left, q);
rce->new_qscale= q;
}
/* smooth curve */
/* find expected bits */
for(i=0; i<rcc->num_entries; i++){
RateControlEntry *rce= &rcc->entry[i];
double factor= rce->qscale / rce->new_qscale;
rce->expected_bits= expected_bits;
expected_bits += (int)(rce->misc_bits + rce->mv_bits + (rce->i_tex_bits + rce->p_tex_bits)*factor + 0.5);
}
// printf("%d %d %f\n", (int)expected_bits, (int)all_available_bits, rate_factor);
if(expected_bits > all_available_bits) rate_factor-= step;
}
return 0;
}
int ff_rate_estimate_qscale_pass2(MpegEncContext *s)
{
int qmin= s->qmin;
int qmax= s->qmax;
float q;
int qscale;
float br_compensation;
double diff;
int picture_number= s->picture_number;
RateControlEntry *rce= &s->rc_context.entry[picture_number];
int64_t wanted_bits= rce->expected_bits;
emms_c();
// printf("%d %d %d\n", picture_number, (int)wanted_bits, (int)s->total_bits);
if(s->pict_type==B_TYPE){
qmin= (int)(qmin*s->b_quant_factor+0.5);
qmax= (int)(qmax*s->b_quant_factor+0.5);
}
if(qmin<2) qmin=2;
if(qmax>31) qmax=31;
if(qmax<=qmin) qmax= qmin;
q= rce->new_qscale;
diff= s->total_bits - wanted_bits;
br_compensation= (s->bit_rate_tolerance - diff)/s->bit_rate_tolerance;
if(br_compensation<=0.0) br_compensation=0.001;
q/=br_compensation;
qscale= (int)(q + 0.5);
if (qscale<qmin) qscale=qmin;
else if(qscale>qmax) qscale=qmax;
// printf("%d %d %d %d type:%d\n", qmin, qscale, qmax, picture_number, s->pict_type); fflush(stdout);
return qscale;
}